Innovation, research and a mammoth volunteering effort by people helped conservationists learn more about wildlife in UK seas, reveals The Wildlife Trusts’ 2024 marine review, published today.

Seaside volunteers clocked over 46,000 thousand hours surveying shorelines and recording wildlife. Discoveries include climate-indicator sea slugs and seaweeds, plus sightings of conger eels and humpback whales.

Groundbreaking research, pioneering nature recovery projects and a complete network of snorkel trails around Scotland also feature in the annual marine round-up.

The Wildlife Trusts – and 80% of the British public – want to see bottom trawling banned in protected areas, and measures to ensure that offshore developments are nature positive. The charities say that strengthening protection of the UK’s blue carbon can help to achieve climate and biodiversity goals.

Ruth Williams, head of marine conservation at The Wildlife Trusts, says:  

“People are central to nature recovery and made huge contributions to our knowledge of UK seas this year. Wildlife surveys and monitoring have led to incredible discoveries, including new species on UK shores. Success stories demonstrate the enormous value of marine conservation and why robust protection is critical for nature recovery.  

“As the first country to map all its blue carbon habitats, the UK has a unique position to champion better protection for seabed habitats. They are the unsung heroes in our fight against climate change. We need policies that stop damaging activities in protected areas, plus continued support for innovation, monitoring and work to improve coastal habitats.” 

Discoveries of climate change indicators and non-native species were made through The Wildlife Trusts’ national intertidal survey programme, Shoresearch, and volunteering days. Highlights include: 

• First records of a warty doris sea slug in Sussex and rainbow sea slug in Devon. 

• First records of devil’s tongue weed and the non-native kelp seaweed, wakame on a Kent shore. Wakame was recorded at Wembury, Devon for the first time. 

• Red-rust bryozoan – a dark-red invertebrate that forms leaf-like structures on rocks – was recorded along the south coast. 

• Pom-pom weed – a seaweed native to Asia that forms red tangled ‘pompoms’ – was found across Devon. It could displace macro-invertebrates, like barnacles. 

• Significant numbers of Asian shore crab on the Naze in Essex over summer. They may affect native crab, fish and shellfish by out-competing for food. 

• Hundreds of mauve jellyfish washed up in Cornwall and on the Isles of Scilly. They are normally found in warmers waters such as the Mediterrranean.  

• Very dense aggregation of invasive pacific oyster at Hope Cove in Devon. They can alter ecosystems through reef formation and displacing native oysters. 

• A loggerhead sea turtle was found in Cumbria and released in the Azores. 

Successful research projects helped conservationists learn more about UK marine habitats and wildlife. The Wildlife Trusts were one of the charities behind The Blue Carbon Mapping Project, which saw the UK become the first country to estimate the carbon stored in its seabed habitats. The report reinforced calls to ban bottom-trawling in Marine Protected Areas (MPAs), as 43% of the UK’s blue carbon is in these zones. 

Monitoring of marine habitats demonstrate how wildlife can recover when areas are properly protected. Highlights include: 

• Giant mussel beds, greater diversity of fish and increased numbers of lobster were reported in Sussex – three years after a byelaw was passed to protect 300km2 of seabed from trawling. A tope shark and European eel were also found among 81 different marine species recorded. 

• Monitoring in the Medway – the largest no-take zone in the UK – found huge numbers of juvenile bass. Shore crabs were also found in abundance.  

• A spiny lobster was found in Wembury Bay, Devon, for the first time in living memory. They are returning following excessive fishing in the 60s and 70s.  

• St Piran’s hermit crabs were recorded in great numbers on the south coast. They were wiped out by the Torrey Canyon Spill of 1967. 

• Surveying at Martlesham Wilds in Suffolk recorded bass, grey mullet and common goby – highlighting the value of saltmarsh as a spawning area. 

New conservation projects include large-scale initiatives in Cornwall and Essex to link conservation efforts on land with protecting important marine and coastal habitats. Other conservation highlights include: 

• The first UK trial of remote setting to reintroduce native oysters in the Humber estuary, allowing seeded oysters to be produced close to where they will grow. 

• Volunteers measured a snakelocks anemone and coral weed bed the size of 5 Olympic swimming pools in Kimmeridge Bay, Dorset – maybe unique in UK seas. 

• Manx Wildlife Trust noted the highest number of seal pups since recording began in 2009. Thermal imaging helped to record 98 pups on the Calf of Man. Almost 1,500 pups were counted in one week at Donna Nook, Lincolnshire.  

• Alderney’s northern gannets – 1% of the global population – became one of the first in the world to be surveyed with drones and Artificial Intelligence. 

• Volunteers gathered by hand over 3,000kg of rubbish from beaches – the weight of three baby humpback whales – in clean-ups organised by Wildlife Trusts. 

People made more wildlife sightings that emphasise the rich biodiversity of UK shores and seas. Highlights include: 

• Humpback whales were seen off Lancashire, Pembrokeshire and North Wales. Over 30 humpbacks were recorded off Cornwall last winter, including ‘Ivy’ who was freed from entanglement by lifeboat crews. 

• A rarely seen sea mouse was seen in Sussex moving through the sands at high tide. The worm is normally found on the seabed. 

• Dozens of conger eels – the largest eel in the world – washed up on a beach in Dorset. It is suspected they were discarded by fishers as bycatch. 

• A black bream caught at Poole Bay contained 38 seahorses – baffling experts.  

• The discovery of small-headed clingfish on the Isle of Man was confirmed as new species for the island. It was found by a volunteer in Douglas Bay. 

UK seas are rich in wildlife but lack abundance due to human-induced pressures. The Wildlife Trusts encourage people to share sightings, join an event or become marine volunteers to contribute to nature recovery at sea.  

The Wildlife Trusts’ marine review 2024 can be read here.